U.S. patent application number 14/973282 was filed with the patent office on 2017-06-22 for earth-boring tools including passively adjustable, agressiveness-modifying members and related methods.
The applicant listed for this patent is Baker Hughes Incorporated. Invention is credited to Juan Miguel Bilen, Jayesh Rameshlal Jain, Gregory L. Ricks, Chaitanya K. Vempati.
Application Number | 20170175455 14/973282 |
Document ID | / |
Family ID | 51728154 |
Filed Date | 2017-06-22 |
United States Patent
Application |
20170175455 |
Kind Code |
A1 |
Jain; Jayesh Rameshlal ; et
al. |
June 22, 2017 |
EARTH-BORING TOOLS INCLUDING PASSIVELY ADJUSTABLE,
AGRESSIVENESS-MODIFYING MEMBERS AND RELATED METHODS
Abstract
Earth-boring tools may include a body and a passively
adjustable, aggressiveness-modifying member secured to the body.
The passively adjustable, aggressiveness-modifying member may be
movable between a first position in which the earth-boring tool
exhibits a first aggressiveness and a second position in which the
earth-boring tool exhibits a second, different aggressiveness
responsive to forces acting on the passively adjustable,
aggressiveness-modifying member.
Inventors: |
Jain; Jayesh Rameshlal; (The
Woodlands, TX) ; Vempati; Chaitanya K.; (Conroe,
TX) ; Ricks; Gregory L.; (Spring, TX) ; Bilen;
Juan Miguel; (The Woodlands, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Baker Hughes Incorporated |
Houston |
TX |
US |
|
|
Family ID: |
51728154 |
Appl. No.: |
14/973282 |
Filed: |
December 17, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 10/633 20130101;
E21B 10/62 20130101; E21B 10/08 20130101; E21B 10/42 20130101; E21B
10/54 20130101; E21B 17/1092 20130101; E21B 7/064 20130101; E21B
10/627 20130101; E21B 10/20 20130101 |
International
Class: |
E21B 10/62 20060101
E21B010/62; E21B 10/42 20060101 E21B010/42; E21B 10/20 20060101
E21B010/20 |
Claims
1. An earth-boring tool, comprising: a body; and a passively
adjustable, aggressiveness-modifying member secured to the body,
the passively adjustable, aggressiveness-modifying member being
movable between a first position in which the earth-boring tool
exhibits a first aggressiveness and a second position in which the
earth-boring tool exhibits a second, different aggressiveness
responsive to forces acting on the passively adjustable,
aggressiveness-modifying member.
2. The earth-boring tool of claim 1, wherein the passively
adjustable, aggressiveness-modifying member comprises one of a
depth-of-cut limiting device, a cutting element, a pad, an ovoid,
and a leg having a rolling cone secured to an end of the leg and
wherein the passively adjustable, aggressiveness modifying member
is movable from the first position at a first longitudinal and
radial position relative to an outer surface of the body to the
second position at a second, different longitudinal position,
radial position, or both longitudinal and radial position relative
to the outer surface of the body.
3. The earth-boring tool of claim 1, wherein the first position
corresponds to an extended state, the second position corresponds
to a retracted state, the passively adjustable,
aggressiveness-modifying member is movable toward the first
position at a first rate, and the passively adjustable,
aggressiveness-modifying member is movable toward the second
position at a second, slower rate.
4. The earth-boring tool of claim 3, wherein the passively
adjustable, aggressiveness-modifying member is biased toward the
first position.
5. The earth-boring tool of claim 3, wherein the passively
adjustable, aggressiveness-modifying member comprises: a
formation-engaging structure; a piston operatively connected to the
formation-engaging structure, the piston positioned to apply a
force on the pad; a biasing member applying a force on the piston
toward the first position; a fluid chamber divided by the piston
into a first fluid chamber and a second fluid chamber; and a first
fluid flow path from the first fluid chamber to the second fluid
chamber that controls movement of the piston toward the first
position at the first rate and a second fluid flow path from the
second chamber to the first chamber that controls movement of the
piston toward the second position at the second rate.
6. The earth-boring tool of claim 5, wherein a first check valve,
first flow restrictor, or first check valve and first flow
restrictor in the first fluid flow path defines the first rate and
a second check valve, second flow restrictor, or second check valve
and second flow restrictor in the second fluid flow path defines
the second rate.
7. The earth-boring tool of claim 5, wherein the piston comprises a
double-acting piston and a fluid acting on a first side of the
double-acting piston controls at least in part the first rate and a
fluid acting on a second, opposite side of the double-acting piston
controls at least in part the second rate.
8. The earth-boring tool of claim 5, wherein the piston is
operatively coupled to the formation-engaging structure by one of:
a direct mechanical connection and via a fluid.
9. The earth-boring tool of claim 1, wherein the earth-boring tool
is a rolling cone drill bit or a hybrid bit and the passively
adjustable, aggressiveness-modifying member is located on a leg
extending from the body of the rolling cone drill bit or hybrid bit
toward a rolling cone secured to an end of the leg, the passively
adjustable, aggressiveness-modifying member enabling the leg to
dampen vibration as the rolling cone engages with an underlying
earth formation.
10. The earth-boring tool of claim 9, further comprising an
additional passively adjustable, aggressiveness-modifying member on
each other leg extending from the body of the rolling cone drill
bit or hybrid bit.
11. The earth-boring tool of claim 1, wherein the earth-boring tool
is a reamer and the passively adjustable, aggressiveness-modifying
member is located on a blade of the reamer, the passively
adjustable, aggressiveness-modifying member being configured to
modify a depth of cut of cutting elements secured to the blade of
the reamer in response to forces applied to the passively
adjustable, aggressiveness-modifying member as the cutting elements
engage with an earth formation.
12. The earth-boring tool of claim 11, further comprising an
additional passively adjustable, aggressiveness-modifying member on
each other blade of the reamer.
13. A method of passively adjusting an aggressiveness of an
earth-boring tool, comprising: causing a force to be exerted on a
passively adjustable, aggressiveness-modifying member secured to a
body; and moving the passively adjustable, aggressiveness-modifying
member from a first position in which the earth-boring tool
exhibits a first aggressiveness to a second position in which the
earth-boring tool exhibits a second, different aggressiveness
responsive to causing the force to act on the passively adjustable,
aggressiveness-modifying member.
14. The method of claim 13, wherein moving the passively
adjustable, aggressiveness-modifying member from the first position
to the second position comprises increasing the aggressiveness of
the earth-boring tool by retracting the passively adjustable,
aggressiveness-modifying member from an extended position, toward
the body, to a retracted position.
15. The method of claim 14, further comprising subsequently
decreasing the aggressiveness of the earth-boring tool by extending
the passively adjustable, aggressiveness-modifying member from the
retracted position, away from the body, to the extended
position.
16. The method of claim 15, wherein retracting the passively
adjustable, aggressiveness-modifying member from the extended
position to the retracted position comprises retracting the
passively adjustable, aggressiveness-modifying member from the
extended position to the retracted position at a first rate and
wherein extending the passively adjustable,
aggressiveness-modifying member from the retracted position to the
extended position comprises extending the passively adjustable,
aggressiveness-modifying member from the retracted position to the
extended position at a second, faster rate.
17. The method of claim 15, wherein extending the passively
adjustable, aggressiveness-modifying member from the retracted
position to the extended position comprises enabling a biasing
member biasing the passively adjustable, aggressiveness-modifying
member toward the extended position to extend the passively
adjustable, aggressiveness-modifying member from the retracted
position to the extended position.
18. The method of claim 13, wherein the passively adjustable,
aggressiveness-modifying member comprises one of a depth-of-cut
limiting device, a cutting element, a pad, an ovoid, and a leg
having a rolling cone secured to an end of the leg and wherein
moving the passively adjustable, aggressiveness-modifying member
from the first position to the second position comprises moving the
passively adjustable, aggressiveness modifying member from a first
longitudinal and radial position relative to an outer surface of
the body to a second, different longitudinal position, radial
position, or both longitudinal and radial position relative to the
outer surface of the body.
19. The method of claim 13, wherein the earth-boring tool is a
rolling cone drill bit or a hybrid bit and the passively
adjustable, aggressiveness-modifying member is located on a leg
extending from the body of the rolling cone drill bit or hybrid bit
toward a rolling cone secured to an end of the leg, and wherein
moving the passively adjustable, aggressiveness-modifying member
from the first position to the second position comprises dampening
vibration experienced by the leg as the rolling cone engages with
an underlying earth formation.
20. The method of claim 13, wherein the earth-boring tool is a
reamer and the passively adjustable, aggressiveness-modifying
member is located on a blade of the reamer, and wherein moving the
passively adjustable, aggressiveness-modifying member from the
first position to the second position comprises modifying a depth
of cut of cutting elements secured to the blade of the reamer in
response to forces applied to the passively adjustable,
aggressiveness-modifying member as the cutting elements engage with
an earth formation.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 13/864,926, filed Apr. 17, 2013, for "DRILL
BIT WITH SELF-ADJUSTING PADS," the disclosure of which is
incorporated herein in its entirety by this reference.
FIELD
[0002] This disclosure relates generally to earth-boring tools and
systems that utilize the same for drilling boreholes in earth
formations. More specifically, disclosed embodiments relate to
earth-boring tools that may include one or more passively
adjustable, aggressiveness-modifying members configured to modify
the aggressiveness of the earth-boring tools in response to forces
acting on the passively adjustable, aggressiveness-modifying
members.
BACKGROUND
[0003] Oil wells (also referred to as "wellbores" or "boreholes")
are drilled with a drill string that includes a tubular member
having a drilling assembly (also referred to as the "bottomhole
assembly" or "BHA"). The BHA typically includes devices and sensors
that provide information relating to a variety of parameters
relating to the drilling operations ("drilling parameters"),
behavior of the BHA ("BHA parameters") and parameters relating to
the formation surrounding the wellbore ("formation parameters"). An
earth-boring tool, such as a drill bit attached to the bottom end
of the BHA, is rotated by rotating the drill string and/or by a
drilling motor (also referred to as a "mud motor") in the BHA to
disintegrate the rock formation to drill the wellbore. A large
number of wellbores are drilled along contoured trajectories. For
example, a single wellbore may include one or more vertical
sections, deviated sections and horizontal sections through
differing types of rock formations. When drilling progresses from a
soft formation, such as sand, to a hard formation, such as shale,
or vice versa, the rate of penetration (ROP) of the drill changes
and can cause (decreases or increases) excessive fluctuations or
vibration (lateral or torsional) in the earth-boring tool. The ROP
is typically controlled by controlling the weight-on-bit (WOB) and
rotational speed (revolutions per minute or "RPM") of the drill bit
so as to control drill bit fluctuations. The WOB is controlled by
controlling the hook load at the surface and the RPM is controlled
by controlling the drill string rotation at the surface and/or by
controlling the drilling motor speed in the BHA. Controlling the
drill bit fluctuations and ROP by such methods requires the
drilling system or operator to take actions at the surface. The
impact of such surface actions on the drill bit fluctuations is not
substantially immediate. Drill bit aggressiveness contributes to
the vibration, whirl and stick-slip for a given WOB and drill bit
rotational speed. "Depth of Cut" (DOC) of a drill bit, generally
defined as "the distance the drill bit advances along axially into
the formation in one revolution", is a contributing factor relating
to the drill bit aggressiveness. Controlling DOC, cutting element
exposure, and other aggressiveness-affecting parameters can provide
a smoother borehole, avoid premature damage to the cutters and
prolong operating life of the earth-boring tool.
BRIEF SUMMARY
[0004] The disclosure herein provides a drill bit and drilling
systems using the same configured to control the rate of change of
instantaneous aggressiveness of an earth-boring tool during
drilling of a wellbore.
[0005] In some embodiments, earth-boring tools may include a body
and a passively adjustable, aggressiveness-modifying member secured
to the body. The passively adjustable, aggressiveness-modifying
member may be movable between a first position in which the
earth-boring tool exhibits a first aggressiveness and a second
position in which the earth-boring tool exhibits a second,
different aggressiveness responsive to forces acting on the
passively adjustable, aggressiveness-modifying member.
[0006] In other embodiments, methods of passively adjusting
aggressivenesses of earth-boring tools may involve causing a force
to be exerted on a passively adjustable, aggressiveness-modifying
member secured to a body. The passively adjustable,
aggressiveness-modifying member may move from a first position in
which the earth-boring tool exhibits a first aggressiveness to a
second position in which the earth-boring tool exhibits a second,
different aggressiveness responsive to the force acting on the
passively adjustable, aggressiveness-modifying member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] While this disclosure concludes with claims particularly
pointing out and distinctly claiming specific embodiments, various
features and advantages of embodiments within the scope of this
disclosure may be more readily ascertained from the following
description when read in conjunction with the accompanying
drawings, in which:
[0008] FIG. 1 is a schematic diagram of an illustrative drilling
system that includes a drill string that has an earth-boring tool
made according to one embodiment of this disclosure;
[0009] FIG. 2 shows a partially cut-away side view of an
illustrative earth-boring tool configured as a fixed-cutter drill
bit with a passively adjustable, aggressiveness-modifying member
and a rate control device for controlling the rates of extending
and retracting the passively adjustable, aggressiveness-modifying
member from a surface of the earth-boring tool, according to one
embodiment of this disclosure;
[0010] FIG. 3 shows an alternative embodiment of the rate control
device that operates the passively adjustable,
aggressiveness-modifying member via a hydraulic line;
[0011] FIG. 4 shows an embodiment of a rate control device
configured to operate multiple passively adjustable,
aggressiveness-modifying members;
[0012] FIG. 5 shows placement of a rate control device of FIG. 4 in
the crown section of the earth-boring tool;
[0013] FIG. 6 shows placement of a rate control device of in fluid
passage or flow path of the earth-boring tool;
[0014] FIG. 7 shows a drill bit, wherein the rate control device
and the passively adjustable, aggressiveness-modifying member are
placed on an outside surface of the earth-boring tool;
[0015] FIG. 8 is a cross-sectional view of another embodiment of an
earth-boring tool configured as a rolling cone drill bit including
a passively adjustable, aggressiveness-modifying member; and
[0016] FIG. 9 is a cross-sectional view of a portion of another
embodiment of an earth-boring tool configured as an expandable
reamer including a passively adjustable, aggressiveness-modifying
member.
DETAILED DESCRIPTION
[0017] The illustrations presented in this disclosure are not meant
to be actual views of any particular drill string, earth-boring
tool, or component thereof, but are merely idealized
representations employed to describe illustrative embodiments.
Thus, the drawings are not necessarily to scale.
[0018] Disclosed embodiments relate generally to earth-boring tools
that may include one or more passively adjustable,
aggressiveness-modifying members configured to modify the
aggressiveness of the earth-boring tools in response to forces
acting on the passively adjustable, aggressiveness-modifying
members. More specifically, disclosed are embodiments of
earth-boring tools that may enable selective increasing and
decreasing of the aggressiveness of the earth-boring tools
utilizing the forces acting on, and corresponding responsive
movement of, passively adjustable, aggressiveness-modifying members
secured to the earth-boring tools.
[0019] Although some embodiments of passively adjustable,
aggressiveness-modifying members in this disclosure are depicted as
being used and employed in earth-boring drill bits, such as
fixed-cutter earth-boring rotary drill bits, sometimes referred to
as "drag" bits, and rolling-cone drill bits, and earth-boring
reamers, such as expandable reamers, passively adjustable,
aggressiveness-modifying members in accordance with this disclosure
may be employed in any earth-boring tool having a cutting structure
susceptible to passive adjustment of its aggressiveness.
Accordingly, the terms "earth-boring tool" and "earth-boring drill
bit," as used in this disclosure, mean and include any type of bit
or tool used for drilling during the formation or enlargement of a
wellbore in a subterranean formation and include, for example,
fixed-cutter drill bits, rolling cone bits, percussion bits, core
bits, eccentric bits, bicenter bits, reamers, mills, hybrid bits,
and other drilling bits and tools known in the art.
[0020] As used in this disclosure, the term "passive" when used in
the context of the adjustment of an aggressiveness-modifying member
means and includes embodiments wherein the adjustment is achieved
without requiring any special-purpose, dedicated electrical or
electromechanical actuation components to accomplish adjustment.
For example, passively adjustable, aggressiveness-modifying members
may lack electronic and electromechanical actuation mechanisms and
may not require dedicated operator triggers (e.g., changing flow
rates of circulating fluid, changing rates of rotation of the drill
string, making such changes in a predetermined pattern) to
accomplish or initiate adjustment. As an additional example,
passively adjustable, aggressiveness-modifying members may be
actuatable utilizing mechanical or hydraulic actuation mechanisms,
and may automatically actuate, deactuate, and otherwise modify
aggressiveness in response to forces inherently acting on the
passively adjustable, aggressiveness-modifying members during
use.
[0021] As used in this disclosure, the tem' "aggressiveness" (.mu.)
of an earth-boring tool is calculated according to the following
formula:
.mu. = 36 .times. T D .times. W ##EQU00001##
wherein T is the torque applied to the earth-boring tool, D is the
diameter of the earth-boring tool, and W is the weight applied to
the earth-boring tool (e.g., weight-on-bit (WOB)). Aggressiveness
is a unitless number. Aggressiveness may be affected by factors
such as vibration, number of blades or cones, cutting element size,
type, and configuration, hardness of the subterranean formation,
etc. These factors may affect the aggressiveness by changing the
torque delivered at a particular applied weight. Different types of
earth-boring tools may exhibit different aggressivenesses. As
illustrative examples, conventional roller cone bits may have a bit
aggressiveness of from about 0.10 to about 0.25, impregnated bits
may have a bit aggressiveness of from about 0.12 to about 0.40, and
fixed-cutter bits may have a bit aggressiveness of from about 0.40
to about 1.50 (assuming, in each case, similar cutting element type
on each blade or roller cone of a bit, and somewhat evenly
distributed applied weight between each blade or roller cone).
Hybrid bits (bits having a combination of roller cones and
fixed-cutter blades) may have a bit aggressiveness between that of
a roller cone bit and a fixed-cutter drill bit.
[0022] FIG. 1 is a schematic diagram of an illustrative drilling
system 100 that may utilize earth-boring tools made according to
the disclosure herein. FIG. 1 shows a wellbore 110 having an upper
section 111 with a casing 112 installed therein and a lower section
114 being drilled with a drill string 118. The drill string 118 is
shown to include a tubular member 116 with a BHA 130 attached at
its bottom end. The tubular member 116 may be made up by joining
drill pipe sections or it may be a coiled-tubing. An earth-boring
tool 150 is shown attached to the bottom end of the BHA 130 for
disintegrating the rock formation 119 to drill the wellbore 110 of
a selected diameter.
[0023] Drill string 118 is shown conveyed into the wellbore 110 by
a rig 180 at the surface 167. The illustrative rig 180 shown is a
land rig for ease of explanation. The apparatus and methods
disclosed herein may also be utilized with an offshore rig used for
drilling wellbores under water. A rotary table 169 or a top drive
(not shown) coupled to the drill string 118 may be utilized to
rotate the drill string 118 to rotate the BHA 130 and thus the
earth-boring tool 150 to drill the wellbore 110. A drilling motor
155 (also referred to as the "mud motor") may be provided in the
BHA 130 to rotate the earth-boring tool 150. The drilling motor 155
may be used alone to rotate the earth-boring tool 150 or to
superimpose the rotation of the earth-boring tool 150 by the drill
string 118. A control unit (or controller) 190, which may be a
computer-based unit, may be placed at the surface 167 to receive
and process data transmitted by the sensors in the earth-boring
tool 150 and the sensors in the BHA 130, and to control selected
operations of the various devices and sensors in the BHA 130. The
surface controller 190, in one embodiment, may include a processor
192, a data storage device (or a computer-readable medium) 194 for
storing data, algorithms and computer programs 196. The data
storage device 194 may be any suitable device, including, but not
limited to, a read-only memory (ROM), a random-access memory (RAM),
a flash memory, a magnetic tape, a hard disk and an optical disk.
During drilling, a drilling fluid 179 from a source thereof is
pumped under pressure into the tubular member 116. The drilling
fluid discharges at the bottom of the earth-boring tool 150 and
returns to the surface via the annular space (also referred as the
"annulus") between the drill string 118 and the inside wall 142 of
the wellbore 110.
[0024] The BHA 130 may further include one or more downhole sensors
(collectively designated by numeral 175). The sensors 175 may
include any number and type of sensors, including, but not limited
to, sensors generally known as the measurement-while-drilling (MWD)
sensors or the logging-while-drilling (LWD) sensors, and sensors
that provide information relating to the behavior of the BHA 130,
such as drill bit rotation (revolutions per minute or "RPM"), tool
face, pressure, vibration, whirl, bending, and stick-slip. The BHA
130 may further include a control unit (or controller) 170 that
controls the operation of one or more devices and sensors in the
BHA 130. The controller 170 may include, among other things,
circuits to process the signals from sensor 175, a processor 172
(such as a microprocessor) to process the digitized signals, a data
storage device 174 (such as a solid-state-memory), and a computer
program 176. The processor 172 may process the digitized signals,
and control downhole devices and sensors, and communicate data
information with the controller 190 via a two-way telemetry unit
188.
[0025] Still referring to FIG. 1, the earth-boring tool 150 may
include a face section (or bottom section) 152. The face section
152 or a portion thereof faces the formation in front of the
earth-boring tool 150 or the wellbore bottom during drilling. The
earth-boring tool 150, in one aspect, includes one or more
passively adjustable, aggressiveness-modifying members 160 that may
be extended and retracted from a selected surface of the
earth-boring tool 150 to passively adjust an aggressiveness of the
earth-boring tool 150. The passively adjustable,
aggressiveness-modifying members 160 may also be referred to as
"pads," "extensible pads," "extendable pads," "adjustable pads,"
"adjustable gage pads," "adjustable cutting elements," "adjustable
cutters," "adjustable inserts," "adjustable ovoids," "adjustable
legs," and "adjustable depth-of-cut controlling devices," depending
on where they are located, which type of earth-boring tool they are
secured to, and they particular configuration they employ. A
suitable actuation device (or actuation unit) 165 in the
earth-boring tool 150 may be utilized to extend and retract one or
more passively adjustable, aggressiveness-modifying members 160
from a surface of the earth-boring tool 150 during drilling (e.g.,
formation or enlargement) of the wellbore 110. In one aspect, the
actuation device 165 may control the rate of extension and
retraction of the passively adjustable, aggressiveness-modifying
members 160. The actuation device is also referred to as a "rate
control device" or "rate controller." In another aspect, the
actuation device is a passive device that automatically adjusts or
self-adjusts the extension and retraction of the passively
adjustable, aggressiveness-modifying members 160 based on, or in
response to, the force or pressure applied to the passively
adjustable, aggressiveness-modifying members 160 during drilling.
The rate of extension and retraction of the passively adjustable,
aggressiveness-modifying members 160 may be preset as described in
more detail in reference to FIGS. 2 through 4.
[0026] FIG. 2 shows an illustrative earth-boring tool 200 made
according to one embodiment of this disclosure. The earth-boring
tool 200 is a polycrystalline diamond compact (PDC), fixed-cutter
bit having a body 201 that includes a neck or neck section 210, a
shank 220, and a crown or crown section 230. The neck 210 has a
tapered upper end 212 having threads 212 thereon for connecting the
earth-boring tool 200 to a box end of the drilling assembly 130
(FIG. 1). The shank 220 has a lower vertical or straight section
222 that is fixedly connected to the crown 230 at a joint 224. The
crown 230 includes a face or face section 232 that faces the
formation during drilling. The crown 230 includes a number of
blades, such as blades 234a, 234b, etc. A typical PDC bit may
include, for example, from three to seven blades. Each blade has a
face (also referred to as a "face section") and a side (also
referred to as a "side section"). For example, blade 234a has a
face 232a and a side 236a, while blade 234b has a face 232b and a
side 236b. The sides 236a and 236b extend along the longitudinal or
vertical axis 202 (e.g., an axis of rotation) of the earth-boring
tool 200. Each blade further may further include a number of
cutters secured thereto. In the particular embodiment of FIG. 2,
blade 234a is shown to include cutters 238a on a portion of the
side 236a and cutters 238b along the face 232a while blade 234b is
shown to include cutters 239a on the side 239a and cutters 239b on
the face 232b.
[0027] Still referring to FIG. 2, the earth-boring tool 200
includes one or more passively adjustable, aggressiveness-modifying
members 250 that extend and retract from a surface 252 of the
earth-boring tool 200. FIG. 2 shows a passively adjustable,
aggressiveness-modifying member 250 movably placed in a cavity or
recess 254 in the crown section 230. As shown in FIG. 2, the
passively adjustable, aggressiveness-modifying member 250 may be
configured as, for example, a pad or depth-of-cut control device
configured to modify a depth of cut of the cutters 238. An
activation device 260 may be coupled to the passively adjustable,
aggressiveness-modifying member 250 to extend and retract the
passively adjustable, aggressiveness-modifying member 250 from a
surface location 252 on the earth-boring tool 200.
[0028] In one aspect, the activation device 260 controls the rate
of extension and retraction of the passively adjustable,
aggressiveness-modifying member 250. In another aspect, the device
260 extends the passively adjustable, aggressiveness-modifying
member 250 at a first rate and retracts the passively adjustable,
aggressiveness-modifying member 250 at a second rate. In
embodiments, the first rate and second rate may be the same or
different rates. In another aspect, the rate of extension of the
passively adjustable, aggressiveness-modifying member 250 may be
greater than the rate of retraction. As noted above, the device 260
also is referred to herein as a "rate control device" or a "rate
controller." In the particular embodiment of the device 260, the
passively adjustable, aggressiveness-modifying member 250 is
directly coupled to the device 260 via a mechanical connection or
connecting member 256.
[0029] In one aspect, the device 260 includes a chamber 270 that
houses a double acting reciprocating member, such as a piston 280,
that sealingly divides the chamber 270 into a first chamber 272 and
a second chamber 274. Both chambers 272 and 274 are filled with a
hydraulic fluid 278 suitable for downhole use, such as oil. A
biasing member, such as a spring 284, in the first chamber 272,
applies a selected force on the piston 280 to cause it to move
outward. Since the piston 280 is connected to the passively
adjustable, aggressiveness-modifying member 250, moving the piston
outward causes the passively adjustable, aggressiveness-modifying
member 250 to extend from the surface 252 of the earth-boring tool
200. In one aspect, the chambers 272 and 274 are in fluid
communication with each other via a first fluid flow path or flow
line 282 and a second fluid flow path or flow line 286. A flow
control device, such as a flow restrictor 285 (e.g., an orifice
plate), a check valve, or a flow restrictor 285 and a check valve,
placed in the fluid flow line 282, may be utilized to control the
rate of flow of the fluid from chamber 274 to chamber 272.
Similarly, another flow control device, such as a check valve 287,
a flow restrictor, or a check valve 287 and a flow restrictor,
placed in fluid flow line 286, may be utilized to control the rate
of flow of the fluid 278 from chamber 272 to chamber 274. The flow
control devices 285 and 287 may be configured at the surface to set
the rates of flow through fluid flow lines 282 and 286,
respectively.
[0030] In one aspect, one or both flow control devices 285 and 287
may include a variable control, biasing device, such as a spring,
to provide a constant flow rate from one chamber to another.
Constant fluid flow rate exchange between the chambers 272 and 274
provides a first constant rate for the extension for the piston 280
and a second constant rate for the retraction of the piston 280
and, thus, corresponding constant rates for extension and
retraction of the passively adjustable, aggressiveness-modifying
member 250. The size of the flow control lines 282 and 286 along
with the setting of their corresponding biasing devices 285 and 287
define the flow rates through lines 282 and 286, respectively, and
thus the corresponding rate of extension and retraction of the
passively adjustable, aggressiveness-modifying member 250. In one
aspect, the fluid flow line 282 and its corresponding flow control
device 285 may be set such that when the earth-boring tool 200 is
not in use, i.e., there is no external force being applied onto the
passively adjustable, aggressiveness-modifying member 250, the
biasing member 280 will extend the passively adjustable,
aggressiveness-modifying member 250 to the maximum extended
position. In one aspect, the flow control line 282 may be
configured so that the biasing member 280 extends the passively
adjustable, aggressiveness-modifying member 250 relatively fast or
suddenly. When the earth-boring tool 200 is in operation, such as
during drilling of a wellbore, the weight applied to the
earth-boring tool 200 may exert an external force on the passively
adjustable, aggressiveness-modifying member 250. This external
force may cause the passively adjustable, aggressiveness-modifying
member 250 to apply a force or pressure on the piston 280 and thus
on the biasing member 284.
[0031] In one aspect, the fluid flow line 286 may be configured to
allow relatively slow flow rate of the fluid from chamber 272 into
chamber 274, thereby causing the passively adjustable,
aggressiveness-modifying member 250 to retract relatively slowly.
As an example, the extension rate of the passively adjustable,
aggressiveness-modifying member 250 may be set so that the
passively adjustable, aggressiveness-modifying member 250 extends
from the fully retracted position to a fully extended position over
a few seconds while it retracts from the fully extended position to
the fully retracted position over one or several minutes or longer
(such as, for example, between two and five minutes). It will be
noted that any suitable rate may be set for the extension and
retraction of the passively adjustable, aggressiveness-modifying
member 250. In one aspect, the device 260 is a passive device that
adjusts the extension and retraction of a passively adjustable,
aggressiveness-modifying member 250 based on or in response to the
force or pressure applied on the passively adjustable,
aggressiveness-modifying member 250.
[0032] When the passively adjustable, aggressiveness-modifying
member 250 is in a first state, the earth-boring tool 200 may
exhibit a first aggressiveness, and the earth-boring tool 200 may
exhibit a second, different aggressiveness when the passively
adjustable, aggressiveness-modifying member 250 is in a second
state. For example, when the passively adjustable,
aggressiveness-modifying member 250 is in a fully extended
position, the earth-boring tool 200 may exhibit a least
aggressiveness, and the earth-boring tool may exhibit a greatest
aggressiveness when the passively adjustable,
aggressiveness-modifying member 250 is in a fully retracted
position. Moreover, the passively adjustable,
aggressiveness-modifying member 250 may automatically adapt the
aggressiveness of the earth-boring tool 200 responsive to forces
inherently acting on the passively adjustable,
aggressiveness-modifying member 250 (e.g., applied weight,
vibrational forces, reaction forces from the formation, applied
torque) to and between the greatest and least aggressivenesses,
enabling the earth-boring tool 200 to adaptively react to drilling
conditions without requiring active intervention from an operator
or complex, active adjustment-controlling mechanisms.
[0033] The passively adjustable, aggressiveness-modifying member
250 may enable the earth-boring tool 200 to effectively drill the
earth formation at lower applied torque for a given applied weight
(e.g., weight on bit (WOB)). For example, the passively adjustable,
aggressiveness-modifying may enable a 5% reduction in applied
torque for a given applied weight or more. More specifically, the
passively adjustable, aggressiveness-modifying may enable, for
example, a 10% reduction in applied torque for a given applied
weight or more. As specific, nonlimiting examples, the passively
adjustable, aggressiveness-modifying may enable a 15%, 25%, 30%,
50%, or 60% reduction in applied torque for a given applied weight
or more.
[0034] FIG. 3 shows an another embodiment of a rate control device
300. The device 300 includes a fluid chamber 370 divided by a
double acting piston 380 into a first chamber 372 and a second
chamber 374. The chambers 372 and 374 are filled with a hydraulic
fluid 378. A first fluid flow line 382 and an associated flow
control device 385 allow the fluid 378 to flow from chamber 374 to
chamber 372 at a first flow rate and a fluid flow line 386 and an
associated flow control device 387 allow the fluid 378 to flow from
the chamber 372 to chamber 374 at a second rate. The piston 380 is
connected to a force transfer device 390 that includes a piston 392
in a chamber 394. The chamber 394 contains a hydraulic fluid 395,
which is in fluid communication with a passively adjustable,
aggressiveness-modifying member 350. In one aspect, the passively
adjustable, aggressiveness-modifying member 350 may be placed in a
chamber 352, which chamber is in fluid communication with the fluid
395 in chamber 394. When the biasing device 384 moves the piston
380 outward, it moves the piston 392 outward and into the chamber
394. Piston 392 expels fluid 395 from chamber 394 into the chamber
352, which extends the passively adjustable,
aggressiveness-modifying member 350. When a force is applied on to
the passively adjustable, aggressiveness-modifying member 350, it
pushes the fluid from chamber 352 into chamber 394, which applies a
force onto the piston 380. The rate of the movement of the piston
380 is controlled by the flow of the fluid through the fluid flow
line 386 and flow control device 387.
[0035] In the particular configuration shown in FIG. 3, the rate
control device 300 is not directly connected to the passively
adjustable, aggressiveness-modifying member 350, which enables
isolation of the device 300 from the passively adjustable,
aggressiveness-modifying member 350 and allows it to be located at
any desired location in the earth-boring tool, as described in
connection with FIGS. 5 and 6. In another aspect, the passively
adjustable, aggressiveness-modifying member 350 may be directly
connected to a cutter 399 or an end of the passively adjustable,
aggressiveness-modifying member 350 may be made as a cutter. In
this configuration, the cutter 399 acts both as a cutter and an
extendable and a retractable, passively adjustable,
aggressiveness-modifying member 350.
[0036] FIG. 4 shows a shared rate control device 400 configured to
operate more than one passively adjustable,
aggressiveness-modifying member, such as passively adjustable,
aggressiveness-modifying members 350a, 350b, . . . 350n. The rate
control device 400 is the same as shown and described in FIG. 2,
except that it is shown to apply force onto the passively
adjustable, aggressiveness-modifying members 350a, 350b, . . . 350n
via an intermediate device 390, as shown and described in reference
to FIG. 3. In the embodiment of FIG. 4, each of the passively
adjustable, aggressiveness-modifying members 350a, 350b . . . 350n
is housed in separate chambers 352a, 352b . . . 352n respectively.
The fluid 395 from chamber 394 is supplied to all chambers 352a,
352b . . . 352n, thereby automatically and simultaneously extending
and retracting each of the passively adjustable,
aggressiveness-modifying members 350a, 350b . . . 350n based on
external forces applied to each such passively adjustable,
aggressiveness-modifying members 350a, 350b . . . 350n during
drilling. In aspects, the rate control device 400 may include a
suitable pressure compensator 499 for downhole use. Similarly any
of the rate controllers made according to any of the embodiments
may employ a suitable pressure compensator.
[0037] FIG. 5 shows an isometric view of an earth-boring tool 500,
wherein a rate control device 560 is placed in a crown section 530
of the earth-boring tool 500. The rate control device 560 is the
same as shown in FIG. 2, but is coupled to a passively adjustable,
aggressiveness-modifying member 550 via a hydraulic connection 540
and a fluid line 542. The rate control device 560 is shown placed
in a recess 580 accessible from an outside surface 582 of the crown
section 530. The passively adjustable, aggressiveness-modifying
member 550 is shown placed at a face location section 552 on the
face 532, while the hydraulic connection 540 is shown placed in the
crown 530 between the passively adjustable,
aggressiveness-modifying member 550 and the rate control device
560. It should be noted that the rate control device 560 may be
placed at any desired location in the earth-boring tool 500,
including in the shank 520 and neck section 510 and the hydraulic
line 542 may be routed in any desired manner from the rate control
device 560 to the passively adjustable, aggressiveness-modifying
member 550. Such a configuration provides flexibility of placing
the rate control device substantially anywhere in the earth-boring
tool 500.
[0038] FIG. 6 shows an isometric view of a earth-boring tool 600,
wherein a rate control device 660 is placed in a fluid passage 625
of the earth-boring tool 600. In the particular tool configuration
of FIG. 6, the hydraulic connection 640 is placed proximate the
rate control device 660. A hydraulic line 670 is run from the
hydraulic connection 640 to the passively adjustable,
aggressiveness-modifying member 650 through the shank 620 and the
crown 630 of the earth-boring tool 600. During drilling, a drilling
fluid flows through the passage 625. To enable the drilling fluid
to flow freely through the passage 625, the rate control device 660
may be provided with a through bore or passage 655 and the
hydraulic connection device 640 may be provided with a flow passage
645.
[0039] FIG. 7 shows an earth-boring tool 700, wherein an integrated
passively adjustable, aggressiveness-modifying member 755 and rate
control device 750 is placed on an outside surface of the
earth-boring tool 700. In one aspect, the device 750 includes a
rate control device 760 connected to a passively adjustable,
aggressiveness-modifying member 755. In one aspect, the device 750
is a sealed unit that may be attached to any outside surface of the
earth-boring tool 700. The rate control device 760 may be the same
as or different from the rate control devices described herein in
connection with FIGS. 2 through 6. In the particular embodiment of
FIG. 7, the passively adjustable, aggressiveness-modifying member
755 is shown connected to a side 720 a of a blade 720 of the
earth-boring tool 700. The device 750 may be attached or placed at
any other suitable location in the earth-boring tool 700.
Alternatively or in addition thereto, the device 750 may be
integrated into a blade so that the passively adjustable,
aggressiveness-modifying member 755 will extend toward a desired
direction from the earth-boring tool 700.
[0040] FIG. 8 is a cross-sectional view of another embodiment of an
earth-boring tool 800 including a passively adjustable,
aggressiveness-modifying member 850. The earth-boring tool 800,
depicted as a roller cone bit, includes a body 802 having three
legs 804 depending from the body 802. A roller cone 806 is
rotatably mounted to a bearing pin 816 on each of the legs 804.
Each roller cone 806 may comprise a plurality of cutters 808 (e.g.,
teeth or inserts) thereon. The earth-boring tool 800 includes a
threaded section 810 at its upper end for connection a drill string
118 (see FIG. 1). The earth-boring tool 800 may include an internal
plenum 812 extending through the body 802 to fluid passageways 814
that extend from the plenum 812 to a bearing system 828 enabling
the roller cones 106 to rotate about the bearing pin 816 as they
engage with an underlying earth formation.
[0041] The passively adjustable, aggressiveness modifying member
850 may be integrated into one or more of the legs 804 of the
earth-boring tool 800, such that each leg 804 including a passively
adjustable, aggressiveness modifying member 850 may be movable with
respect to the body 802. For example, the passively adjustable,
aggressiveness modifying member 850 may include a bottom portion
820 of the leg 804, proximate the bearing pin 816 and separated
from the body 802 by an upper portion 822 of the leg 804. The
bottom portion 820 of the leg 804 may be movable in a direction D
at least substantially parallel to a longitudinal axis 824 (e.g.,
an axis of rotation) of the earth-boring tool 800. The upper
portion 822 of the leg 804 may include a recess 826 extending into
the leg 804 toward the body 802, the recess 826 being sized and
shaped to receive a rate control device 860 therein. The rate
control device 860 may be the same as, or different from, the rate
control devices described herein in connection with FIGS. 2 through
7.
[0042] When the earth-boring tool 800 is deployed in a borehole,
the passively adjustable, aggressiveness modifying member 850 may
move between a first, fully extended state and a second, fully
retracted state in response to forces acting on the passively
adjustable, aggressiveness modifying member 850. For example, the
passively adjustable, aggressiveness modifying member 850 may
dampen vibrations experienced by the earth-boring tool 850 by
moving between a first, lowest longitudinal position along the
longitudinal axis 824 and second, highest longitudinal position
along the longitudinal axis 824, dampening vibration experienced by
the earth-boring tool 800.
[0043] FIG. 9 is a cross-sectional view of a portion of another
embodiment of an earth-boring tool 900 including a passively
adjustable, aggressiveness-modifying member 950. The earth-boring
tool 900, depicted in FIG. 9 as an expandable reamer, may include
sliding blades 904 positionally retained in a circumferentially
spaced relationship in a generally cylindrical tubular body 902 of
the earth-boring tool. Each blade 904 may include cutters 908
secured thereto, the cutters 908 being configured to engage with,
and remove earth material from, a sidewall of a borehole. The
blades 904 are movable relative to the tubular body 902 during use
of the earth-boring tool 200 between a retracted position and an
extended position responsive to application of hydraulic
pressure.
[0044] The passively adjustable, aggressiveness modifying member
950 may be configured as one or more of the cutters 908 (e.g., PDC
cutting elements, impregnated inserts, or inserts of wear resistant
material (e.g., metal-matrix-cemented tungsten carbide)) of the
earth-boring tool 900. A passively adjustable, aggressiveness
modifying member 950 may be included on each blade 904 in some
embodiments. In other embodiments, a passively adjustable,
aggressiveness-modifying member may be secured to fewer than all
blades 904 of the earth-boring tool 900. The passively adjustable,
aggressiveness modifying member 950 may be movable in a direction D
oriented perpendicular to, or at an oblique angle relative to, a
longitudinal axis 924 (e.g., an axis of rotation) of the
earth-boring tool 900. The blade 904 may include a recess 926
extending into the blade 904 toward the body 902, the recess 926
being sized and shaped to receive a rate control device 960
therein. The rate control device 960 may be the same as, or
different from, the rate control devices described herein in
connection with FIGS. 2 through 8.
[0045] When the earth-boring tool 900 is deployed in a borehole,
the passively adjustable, aggressiveness modifying member 950 may
move between a first, fully extended state and a second, fully
retracted state in response to forces acting on the passively
adjustable, aggressiveness modifying member 950. For example, the
passively adjustable, aggressiveness modifying member 950 may
transition between an overexposed and an underexposed state
relative to the other cutters 908 by moving between a first,
outermost radial position from the longitudinal axis 924 and
second, innermost radial position from the longitudinal axis 924,
responsive to lateral forces from the sidewall of the borehole.
[0046] Thus, in various embodiments, a rate controller may be a
hydraulic actuation device and may be placed at any desired
location in the earth-boring tool or outside the earth-boring tool
to self-adjust extension and retraction of one or more passively
adjustable, aggressiveness-modifying members based on or in
response to external forces applied on the passively adjustable,
aggressiveness-modifying members during drilling of a wellbore. The
passively adjustable, aggressiveness-modifying members may be
located and oriented independently from the location and/or
orientation of the rate controller in the earth-boring tool.
Multiple passively adjustable, aggressiveness-modifying members may
be inter-connected and activated simultaneously. Multiple passively
adjustable, aggressiveness-modifying members may also be connected
to a shared rate controller.
[0047] In various embodiments, during stick-slip, the passively
adjustable, aggressiveness-modifying members can extend relatively
quickly at high rotational speed (RPM) of the earth-boring tool
when the depth of cut (DOC) of the cutters is low. However, at low
RPM, when the DOC start increasing suddenly, the pads resist sudden
inward motion and create a large contact (rubbing) force preventing
high DOC. Limiting high DOC during stick-slip reduces the high
torque build-up and mitigates stick-slip. In various embodiments,
the rate controller may allow sudden or substantially sudden
extension (outward motion) of a passively adjustable,
aggressiveness-modifying member and limit sudden retraction (inward
motion) of the passively adjustable, aggressiveness-modifying
member. Such a mechanism may prevent sudden increase in the depth
of cut of cutters during drilling. A pressure compensator may be
provided to balance the pressures inside and outside the cylinder
of the rate controller.
[0048] Additional, nonlimiting embodiments within the scope of this
disclosure follow:
Embodiment 1
[0049] An earth-boring tool, comprising: a body; and a passively
adjustable, aggressiveness-modifying member secured to the body,
the passively adjustable, aggressiveness-modifying member being
movable between a first position in which the earth-boring tool
exhibits a first aggressiveness and a second position in which the
earth-boring tool exhibits a second, different aggressiveness
responsive to forces acting on the passively adjustable,
aggressiveness-modifying member.
Embodiment 2
[0050] The earth-boring tool of Embodiment 1, wherein the passively
adjustable, aggressiveness-modifying member comprises one of a
depth-of-cut limiting device, a cutting element, a pad, an ovoid,
and a leg having a rolling cone secured to an end of the leg and
wherein the passively adjustable, aggressiveness modifying member
is movable from the first position at a first longitudinal and
radial position relative to an outer surface of the body to the
second position at a second, different longitudinal position,
radial position, or both longitudinal and radial position relative
to the outer surface of the body.
Embodiment 3
[0051] The earth-boring tool of Embodiment 1 or Embodiment 2,
wherein the first position corresponds to an extended state, the
second position corresponds to a retracted state, the passively
adjustable, aggressiveness-modifying member is movable toward the
first position at a first rate, and the passively adjustable,
aggressiveness-modifying member is movable toward the second
position at a second, slower rate.
Embodiment 4
[0052] The earth-boring tool of Embodiment 3, wherein the passively
adjustable, aggressiveness-modifying member is biased toward the
first position.
Embodiment 5
[0053] The earth-boring tool of Embodiment 3 or Embodiment 4,
wherein the passively adjustable, aggressiveness-modifying member
comprises: a formation-engaging structure; a piston operatively
connected to the formation-engaging structure, the piston
positioned to apply a force on the pad; a biasing member applying a
force on the piston toward the first position; a fluid chamber
divided by the piston into a first fluid chamber and a second fluid
chamber; and a first fluid flow path from the first fluid chamber
to the second fluid chamber that controls movement of the piston
toward the first position at the first rate and a second fluid flow
path from the second chamber to the first chamber that controls
movement of the piston toward the second position at the second
rate.
Embodiment 6
[0054] The earth-boring tool of Embodiment 5, wherein a first check
valve, first flow restrictor, or first check valve and first flow
restrictor in the first fluid flow path defines the first rate and
a second check valve, second flow restrictor, or second check valve
and second flow restrictor in the second fluid flow path defines
the second rate.
Embodiment 7
[0055] The earth-boring tool of Embodiment 5 or Embodiment 6,
wherein the piston comprises a double-acting piston and a fluid
acting on a first side of the double-acting piston controls at
least in part the first rate and a fluid acting on a second,
opposite side of the double-acting piston controls at least in part
the second rate.
Embodiment 8
[0056] The earth-boring tool of any one of Embodiments 5 through 7,
wherein the piston is operatively coupled to the formation-engaging
structure by one of: a direct mechanical connection and via a
fluid.
Embodiment 9
[0057] The earth-boring tool of any one of Embodiments 1 through 8,
wherein the earth-boring tool is a rolling cone drill bit or a
hybrid bit and the passively adjustable, aggressiveness-modifying
member is located on a leg extending from the body of the rolling
cone drill bit or hybrid bit toward a rolling cone secured to an
end of the leg, the passively adjustable, aggressiveness-modifying
member enabling the leg to dampen vibration as the rolling cone
engages with an underlying earth formation.
Embodiment 10
[0058] The earth-boring tool of Embodiment 9, further comprising an
additional passively adjustable, aggressiveness-modifying member on
each other leg extending from the body of the rolling cone drill
bit or hybrid bit.
Embodiment 11
[0059] The earth-boring tool of any one of Embodiments 1 through 8,
wherein the earth-boring tool is a reamer and the passively
adjustable, aggressiveness-modifying member is located on a blade
of the reamer, the passively adjustable, aggressiveness-modifying
member being configured to modify a depth of cut of cutting
elements secured to the blade of the reamer in response to forces
applied to the passively adjustable, aggressiveness-modifying
member as the cutting elements engage with an earth formation.
Embodiment 12
[0060] The earth-boring tool of Embodiment 11, further comprising
an additional passively adjustable, aggressiveness-modifying member
on each other blade of the reamer.
Embodiment 13
[0061] A method of passively adjusting an aggressiveness of an
earth-boring tool, comprising: causing a force to be exerted on a
passively adjustable, aggressiveness-modifying member secured to a
body; and moving the passively adjustable, aggressiveness-modifying
member from a first position in which the earth-boring tool
exhibits a first aggressiveness to a second position in which the
earth-boring tool exhibits a second, different aggressiveness
responsive to causing the force to act on the passively adjustable,
aggressiveness-modifying member.
Embodiment 14
[0062] The method of Embodiment 13, wherein moving the passively
adjustable, aggressiveness-modifying member from the first position
to the second position comprises increasing the aggressiveness of
the earth-boring tool by retracting the passively adjustable,
aggressiveness-modifying member from an extended position, toward
the body, to a retracted position.
Embodiment 15
[0063] The method of Embodiment 14, further comprising subsequently
decreasing the aggressiveness of the earth-boring tool by extending
the passively adjustable, aggressiveness-modifying member from the
retracted position, away from the body, to the extended
position.
Embodiment 16
[0064] The method of Embodiment 15, wherein retracting the
passively adjustable, aggressiveness-modifying member from the
extended position to the retracted position comprises retracting
the passively adjustable, aggressiveness-modifying member from the
extended position to the retracted position at a first rate and
wherein extending the passively adjustable,
aggressiveness-modifying member from the retracted position to the
extended position comprises extending the passively adjustable,
aggressiveness-modifying member from the retracted position to the
extended position at a second, faster rate.
Embodiment 17
[0065] The method of Embodiment 15 or Embodiment 16, wherein
extending the passively adjustable, aggressiveness-modifying member
from the retracted position to the extended position comprises
enabling a biasing member biasing the passively adjustable,
aggressiveness-modifying member toward the extended position to
extend the passively adjustable, aggressiveness-modifying member
from the retracted position to the extended position.
Embodiment 18
[0066] The method of any one of Embodiments 13 through 17, wherein
the passively adjustable, aggressiveness-modifying member comprises
one of a depth-of-cut limiting device, a cutting element, a pad, an
ovoid, and a leg having a rolling cone secured to an end of the leg
and wherein moving the passively adjustable,
aggressiveness-modifying member from the first position to the
second position comprises moving the passively adjustable,
aggressiveness modifying member from a first longitudinal and
radial position relative to an outer surface of the body to a
second, different longitudinal position, radial position, or both
longitudinal and radial position relative to the outer surface of
the body.
Embodiment 19
[0067] The method of any one of Embodiments 13 through 18, wherein
the earth-boring tool is a rolling cone drill bit or a hybrid bit
and the passively adjustable, aggressiveness-modifying member is
located on a leg extending from the body of the rolling cone drill
bit or hybrid bit toward a rolling cone secured to an end of the
leg, and wherein moving the passively adjustable,
aggressiveness-modifying member from the first position to the
second position comprises dampening vibration experienced by the
leg as the rolling cone engages with an underlying earth
formation.
Embodiment 20
[0068] The method of any one of Embodiments 13 through 18, wherein
the earth-boring tool is a reamer and the passively adjustable,
aggressiveness-modifying member is located on a blade of the
reamer, and wherein moving the passively adjustable,
aggressiveness-modifying member from the first position to the
second position comprises modifying a depth of cut of cutting
elements secured to the blade of the reamer in response to forces
applied to the passively adjustable, aggressiveness-modifying
member as the cutting elements engage with an earth formation.
[0069] While certain illustrative embodiments have been described
in connection with the figures, those of ordinary skill in the art
will recognize and appreciate that the scope of this disclosure is
not limited to those embodiments explicitly shown and described in
this disclosure. Rather, many additions, deletions, and
modifications to the embodiments described in this disclosure may
be made to produce embodiments within the scope of this disclosure,
such as those specifically claimed, including legal equivalents. In
addition, features from one disclosed embodiment may be combined
with features of another disclosed embodiment while still being
within the scope of this disclosure, as contemplated by the
inventors.
* * * * *